In home theatre, typical surround sound is performed using 5 or 7 loudspeakers plus a subwoofer, such as in the Dolby surround format. Such surround sound systems are able to create direct fields from various directions and ambient (diffuse) fields, but they cannot perform a full ambisonics reproduction that is required to recreate a sound over a spatial area or volume.
The more high-end and complex ambisonics surround sound systems typically require a large circular or spherical arrangement of loudspeaker drivers surrounding the sound control region to reproduce a spatial sound field. However, the requirement for such large arrays of loudspeakers is not compatible with the demands for compact surround sound systems in home theatre and entertainment systems.
A fundamental challenge to sound field control is the presence of room reverberation. Many current surround sound systems simply ignore the presence of room reverberation, although there are some possibilities for avoiding reverberation or cancelling reverberation outside the sound control region [4-8,22]
In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.
It is an object of the present invention to provide an improved compact surround sound system that is capable of reproducing spatial sound fields with a reduced number loudspeakers, or to at least provide the public with a useful choice.